This invention relates to a portable torch, and in particular to a portable hand torch for use with for example disposable propane containers, or quick disconnects hooked up to a natural gas supply.
A review of the patent literature reveals that portable torches for attachment to gas tanks or containers are by no means new. Examples of such torches are found in U.S. Pat. Nos. 3,220,459, which issued to E. D. Wilson on Nov. 30, 1965; 3,280,881, which issued to F. Hach Jr. et al on Oct. 25, 1966; 3,574,506, which issued to J. K. Locke on April 13, 1971 and 4,348,172, which issued to H. C. Miller on Sept. 7, 1982. In general, the prior art devices are found to be somewhat complicated in terms of structure and/or operation. Moreover, with some devices there exists the danger of so-called blowback in which burning of the propane occurs in the body of the torch.
The object of the present invention is to overcome the above identified problems by providing a relatively simple portable torch, which following ignition ensures that burning occurs only at the discharge or burner nozzle end of the torch.
Accordingly, the invention relates to a portable hand torch for attachment to a gaseous fuel source comprising elongated barrel means; handle means on one end of said barrel means; inlet passage means in said handle means for feeding gas from a gaseous fuel source to said barrel means; coupler means in said handle means for connecting a gaseous fuel tank to said inlet passage means; elongated burner tube means on the other end of said barrel means for receiving gas from the gaseouse fuel tank; burner nozzle means on an outer free end of said burner tube means for burning fuel; retention gas line means in said barrel means for carrying fuel from the inlet passage means to said burner nozzle means; venturi passage means in said barrel means for carrying fuel from said inlet passage means to the inlet end of said burner tube means; restricted orifice means in said venturi passage means for limiting the quantity of fuel entering the venturi passage means from said inlet passage means; inlet opening means in said venturi passage means for introducing air into said venturi passage means for mixing with the fuel entering said venturi passage means through said restricted orifice means; spark producing means in said venturi passage means for igniting the mixture of air and fuel in said venturi passage means, whereby, when fuel is fed into said inlet passage means under pressure, the fuel flows through the retention gas line means and said venturi passage means, and once ignition has been achieved in said venturi passage means flame passes through said burner tube means to ignite fuel from said retention gas line means, and thereafter burning is limited to the area of the burner nozzle means.